Ontario Water Damage Restoration for Homes and Warehouses

Built on Foothill Drainage From Day One

Ontario sits at about 1,004 feet on the valley floor of the western Inland Empire, roughly 35 miles east of downtown Los Angeles. The San Gabriel Mountains rise to the north, and Cucamonga Creek and Chino Creek carry runoff south toward the Santa Ana River. Beneath the city is the Chino Basin groundwater area.

Water management is part of the city's origin story. When the Chaffey brothers founded Ontario in 1881-1882, they engineered a drainage system that channeled water from the foothills to the flatter land below, both to irrigate crops and to hold back the floods that periodically hit the area. The brothers also created Euclid Avenue, known for its wide lanes and landscaped median.

Today the average year brings about 11.64 inches of precipitation, with February the wettest month at a little over 3 inches. That is not much, but most of it comes in a few storms, and dry soil and paved surfaces send it running fast.

Santa Ana Winds and the Roof Leaks That Follow

Santa Ana winds hit Ontario frequently in autumn and winter. Strong gusts can lift shingles, crack tiles, loosen flashing and knock debris into gutters. The damage often goes unnoticed until the next rain, when water shows up as a ceiling stain, a drip at a light fixture or wet insulation in the attic.

• After a wind event, look for missing or shifted roofing from the ground.
• Clear leaves and debris from gutters and downspouts before storms.
• Check the attic with a flashlight for damp decking or insulation.
• Put a tarp over obvious damage only if it is safe to do so.

When wind and rain combine, storm damage cleanup usually covers both the roof opening and the wet materials inside. Call (888) 817-5061 to be connected with a local company that can help.

From Postwar Homes to Ontario Ranch

Ontario's housing reflects several eras. Like many Southern California suburbs, the city had a big housing boom during and after World War II, so older neighborhoods near downtown and along the Euclid Avenue corridor include many homes that are now decades old. Galvanized or aging supply pipes, older water heaters and original drain lines are common sources of slow leaks and sudden failures in houses of that age.

In the south, the former agricultural preserve was rezoned in 1999 for residential and commercial use and is now developing as Ontario Ranch (New Haven), though dairies and farms remain nearby. Newer construction has its own weak points: washing machine hoses, refrigerator ice-maker lines, PEX fittings and tankless water heater connections.

Whichever kind of house you live in, quick water extraction keeps a leak from wicking into drywall and cabinets.

Storm History in the Western Inland Empire

San Bernardino County flood control records describe how severe storms have affected the region. The March 2-3, 1938 flood killed 14 county residents and isolated nearly every community. In 1969, two floods a month apart caused more than $23 million and then $31 million in county losses. A 1978 storm critically eroded the Cucamonga Channel levees.

Modern channels and basins handle most runoff, but heavy storms can still overwhelm local storm drains, flood low streets and push water into garages and ground-floor rooms. Report clogged drains or street flooding through the City's Report an Issue portal or the myOntario app. For water that has already come inside, see flood cleanup.

Right After You Find Water

1. Stop it at the source by closing the main shutoff or the fixture valve.
2. Protect yourself from electrical hazards. Never stand in water near plugged-in devices, and reach the breaker only from a dry spot.
3. Note what kind of water it is. Clean supply water, gray water from appliances and contaminated storm water all call for different handling.
4. Photograph and film the source, the affected rooms and any damaged belongings.
5. Call for help. (888) 817-5061 is answered 24/7, and we can connect you with a local professional.

What a Restoration Crew Does on Site

Water damage repair in Ontario starts with an inspection and moisture map, using meters and thermal cameras to see where water traveled under flooring and inside walls. The crew extracts standing water, removes materials that cannot be saved and sets up air movers and dehumidifiers for controlled structural drying. Daily readings show when walls, subfloors and cabinets are back to normal. Then the work moves to rebuilding: drywall, paint, flooring and trim.

Mold is the main reason not to wait. EPA guidance indicates growth can start within 24 to 48 hours on materials that stay wet. California does not seem to have a mold-specific state license, but mold remediation that involves construction falls under CSLB licensing, which since January 1, 2025, applies to jobs of $1,000 or more in labor and materials or any permitted job. Verify any contractor on CSLB's Check a License tool and ask about training, such as IICRC certification. Read more about mold removal.

Distribution Centers, Offices and Insurance Claims

Warehousing and service industries dominate Ontario's economy, and Ontario International Airport is one of the busiest cargo airports in the country. A roof drain backup, a sprinkler line break or storm water at a dock door can wet a very large floor area fast. Facility managers can call (888) 817-5061 to reach a local provider equipped for commercial drying.

Homeowners should know that standard homeowners policies do not include flood, mudslide or debris flow coverage, according to the California Department of Insurance. NFIP flood policies can add mudflow protection, but not landslide coverage, and generally begin about 30 days after purchase. Report damage promptly, keep photos and drying records, and save every receipt. WaterQ also serves callers in Rancho Cucamonga and Corona.

Ontario Areas and Surrounding Cities

WaterQ connects callers throughout Ontario and neighboring Inland Empire and Pomona Valley communities with independent local restoration companies.

Neighborhoods

• Downtown Ontario
• Historic Euclid Avenue corridor
• Ontario Ranch
• New Haven
• Ontario International Airport area

Nearby communities

• Upland
• Rancho Cucamonga
• Montclair
• Chino
• Pomona
• Fontana
• Eastvale
• Jurupa Valley
• Claremont

Local emergency and flood resources

Official sources for alerts, flood maps and preparedness in and around Ontario:

• City of Ontario - Report an Issue
• myOntario phone app
• San Bernardino County Flood Control - Flood preparedness
• FEMA Flood Map Service Center